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Scotty, The Naked Time, stardate 1704.3, Episode 7

Dengue: betting on homeopathy?

Posted by apgaylard on May 8, 2009

bigstockphoto_Doubt_In_The_Casino_4852680By any rational measure, betting on the effectiveness of homeopathy is not a good bet.  However, many thousands of people take this chance: homeopaths stake their livelihood on it; patients bet their money, hopes and sometimes health.  Medical professionals and researchers have effectively staked their careers and reputations on homeopathy working, or at least looking like it does. 

Of course, confirmation bias, the self-limiting nature of many commonly treated ailments and the placebo effect all help improve the odds.  Add to that a general lack of awareness of scientific methods and principles among public and policy-makers alike and betting on homeopathy is starting to look less risky. 

Thinking about the research paper on homeopathy and dengue fever I’ve been looking at recently made me reflect on other possible risk reduction strategies used, subconsciously I’m sure, by the homeopathic community. 

This reflection was prompted by reading a press release (translation)* issued by the author’s employers, The City of Macaé (Rio de Janeiro, Brazil).  What caught my eye was the shift in emphasis on the claims made for the work.  The journal paper majors on prevention and treatment: 

  • “The incidence of the disease in the first three months of 2008 fell 93% …”
  • “[…] these results suggest that homeopathy may be an effective adjunct in Dengue outbreak prevention.”
  • “The remedy was prescribed in single doses, 2 drops p.o. for prevention purposes.”
  • “The intention was to diminish individual and collective susceptibility to the disease and minimize symptoms in those already or later ill.”
  • “The use of homeopathy may be a useful adjunct the control of epidemics […]”
  • “Homeopathic remedies can help to minimize the progression and severity of the disease and to prevent endemic and epidemic diseases, particularly those where no vaccinations are yet available.”

 Yet the press release is all about symptomatic relief.  Nunes is quoted as saying the, “homeopathic complex is used to reduce the symptoms of dengue”**

This tack is similar to a report (translation) apparently carried in a local newspaper, O Fluminense, where Nunes is quoted as saying, “It reminded once again that the complex is not a vaccine, just not immunizes against dengue, but helps in controlling the symptoms, avoiding the worsening of the disease***

It might be that these statements lose something in the limited on-line translation* I’ve performed, but it does look like these claims are more modest than those made a few months later in the ‘research’ paper. 

It is true that the paper talks about reducing the “severity of the disease”; but its main focus is on preventing its spread – reducing the number of people who get infected.  And the main outcome measured in the study was the reduction in reported cases of dengue, clearly interpreted by the author as an indicator that fewer people were actually infected.  It was also claimed to hasten “complete remission” in symptomatic patients. 

This difference in emphasis made me wonder: why were the statements offered to the local press more modest than those in the more research paper?  Why the shifting goal posts? 

It’s just my opinion, of course, but I can think of some possible advantages.  Given that betting on homeopathy is not a good bet at all, as it’s not going to be the cause of the improvements reported for the incidence of dengue in Macaé, how could the odds be improved? 

Clearly, compliance with the conventional preventative measures included in the campaign is vital:  there is every chance that any impact the campaign has is a result of actions like: vector control, surveillance, public awareness etc.  Undermining these by allowing people to think that homeopathy could actually protect them against becoming infected would be extremely irresponsible.  It would also inevitably lead to increased incidence of dengue in the future: betting on homeopathy alone is not a good bet.  And that’s not good for homeopaths either: if the emperor has no clothes it’s best to have the parade at night! 

It’s also important to manage expectations: not putting comments in the local mainstream media that would set the bar for success too high in subsequent years.  If the campaign in Macaé had benefitted from the “play your cards right” fallacy – starting when infections were running high and likely to fall – shifting the focus to something more vague, like reducing the perceived severity of symptoms would be helpful.  In this case, subtly moving the goalposts is a good insurance policy. 

In my opinion, both of these are useful strategies for reducing the risk of homeopathy being exposed as useless in areas where the campaign has already been deployed.  However, such modesty is unlikely to sell the idea to other cities.  That is not such good news for homeopaths.  This is where the more bullish pitch of the research paper and subsequent conference poster makes sense to me. 

Interestingly, my musings do seem to be borne out by reports coming out of Coronel Fabriciano, a dengue-blighted city some 560 km from Rio de Janeiro.  Nunes appears to have been involved with promoting the ‘homeopathic’ approach here.  In February 2009 a local paper, Jornal Hoje em Dia, reported statements promoting a ‘homeopathy campaign’ against dengue.  This included some comments from Nunes. 

ProMed Mail – an internet-based reporting system run by International Society for Infectious Diseases – carried an English translation of the piece. 

“Coronel Fabriciano, the city with the 3rd highest rate of infestation of _Aedes aegypti_ in Minas Gerais state (6.9 per cent [house infestation rate]), added 2 deaths of suspected DHF (dengue hemorrhagic fever), causing the Municipality of Coronel Fabriciano to take more energetic measures to contain a possible epidemic. The betting is on homeopathy. Joint efforts  will be made starting tomorrow, across the city, so that the population of  about 105 000 inhabitants, take without charge the 2 drops of a homeopathic  remedy that promises to decrease the body’s susceptibility to dengue [virus  infection], and mitigate the effects of the disease.

The novel [treatment] comes from the city of Macae (Rio de Janeiro), [carried out at] the hands of homeopath and medical coordinator of the Public Health of the Municipality of that city, Leila Nunes. According to specialists, while the neighboring cities recorded up to a 300 per cent increase of the disease, Macae had a significant reduction in its [dengue] indices. “After distributing the product, reported dengue cases were reduced by up to 65 per cent in 2008, compared to the previous year [2007].  In the 1st 3 months of 2008, compared with the same period of 2007, the rate of dengue cases fell by 93 per cent. We started the application [of the drug] in the population during the peak of the epidemic. We noticed the drop in cases that still occurred that year [2008], but was much more abrupt than in years earlier,” said the doctor. […]”

Reducing the symptoms of the disease still features in the report, but the focus is very similar to that of the research paper: prevention.  Clearly, this sales pitch relies on the reduction of infections. 

To me, this looks like a marketing strategy: down-play the more risky ‘hard’ measure where the ‘homeopathy’ campaign has already been established.  After all, the brand has already been established.  However, to conquer new markets: talk it up – at least until you’ve got a foothold. 

There is, of course, another risk-reduction strategy embedded in this approach: the magician’s misdirection. The campaign is touted as a ‘homeopathic’ intervention, but there’s the “great social mobilization” aspect of the campaign at work as well!  This contains many other measures – which are overwhelmingly the likely source of any benefit.   This sleight of hand is seen in the journalist contending that, “The betting is on homeopathy” when the article goes on to quote the City Prefect, Chico Simoes, describing the more conventional aspects of the campaign: 

“We created a volunteer cleanup force, for “project clean up stuff”, [public] awareness campaigns, and the dial-dengue [information telephone line]. We have more health workers than recommended by the Ministry Health and most recently passed a law authorizing the city government to impose fines of BRL 680 to BRL 1380 [USD 300-609] for people who do not cooperate in the elimination the focus [breeding sites] of _Aedes aegypti_. Still, the index of infestation is high. Lack of awareness in the population and this will take time to change. Dengue in Fabriciano may worsen still further […]”

This sounds very much like the “great social mobilization against dengue” that Nunes told me formed part of the approach in Macaé.  In Coronel Fabriciano they even deployed the Army: 

“Military Armed Forces will also tackle the mosquito transmits dengue [virus] in the state. Today [8 Feb 2009] ends the training course given by the state Secretariat for 100 soldiers of the 12th Infantry Battalion (IB) of Belo Horizonte. Another 200 soldiers will be trained in next 2 weeks to participate in activities in the region or in other cities in the state. The participation of the Armed Forces to fight _Aedes aegypti_ was through an agreement between the Ministries of Health and Defense. The idea is to train 2000 soldiers in Brazil.

This 1st group of soldiers must act initially intersectorially in the 9 regions of the Belo Horizonte prefecture and in surrounding towns that have registered large numbers of mosquito infestations or that have few staff for health and zoonoses control [available] to make visits and to combat outbreaks. In training, the military were introduced to [diflubenzuron], a new insecticide that will be adopted, that is more effective and less toxic.

 The elements seen in the campaign in Macaé appear to be in place: a high rate of infections maximising the chance of a subsequent reduction (play your cards right) and an aggressive programme of conventional countermeasures (magician’s misdirection).

If the number of dengue infections in Coronel Fabriciano go down in 2009 it’s a good bet that the headlines will be about the wonders of homeopathy.  And if this year’s numbers aren’t as good in Macaé: I’d give good odds that the focus will be on the more modest claims released to the local press.

Now, I could be wrong; this is just my opinion.  Neither am I suggesting a conscious deception; in fact I’m convinced that Nunes has a sincere belief homeopathy (translation).  Perhaps as a consequence, it seems to me like betting on homeopathy is being made into a one-way bet.  A combination of goal post shifting and misdirection is staking the deck in favour of the interests of homeopaths and the suppliers of these ‘remedies’. 

However, there are losers.  Public funds and resources will be squandered on administering rites with magic water.  The public understanding of how the human body works will continue to be undermined; ditto for the public’s appreciation of the values, methods and knowledge embodied in science.  And occasionally someone will be tempted to think that homeopathy actually works and will try to use it as an alternative to medicine for something serious.  Among these will be the biggest losers of all. 


Nunes LAS. Contribution of homeopathy to the control of an outbreak of dengue in Macaé, Rio de Janeiro. Int J High Dilution Res [online]. 2008 [cited 2009 May 07]; 7(25): 186-192. Available from: http://www.feg.unesp.br/~ojs/index.php/ijhdr/article/view/315/374 

Oliveira, G. [Macaé: success of the campaign against dengue in international conference]. City of Macaé, 18th September 2008. http://www.macae.rj.gov.br/noticias/mostranot.asp?id=14229   Accessed 07 May 2009. 

ProMED-mail. PRO/EDR> Dengue/DHF update 2009.  ProMED-mail 2009; 10 Feb: 20090210.0610. http://www.promedmail.org . Accessed 07 May 2009. 


Mojo on the Bad Science Forum for the colourful “play your cards right” fallacy. 


*All translations performed with Google Translator. Sorry.

**o complexo homeopático é usado para diminuir os sintomas da dengue.

***Cabe lembrar mais uma vez que o complexo não é uma vacina, logo não imuniza contra a dengue, mas auxilia no controle dos sintomas, evitando o agravamento da doença


9th May 2009. Some minor typos corrected.



6 Responses to “Dengue: betting on homeopathy?”

  1. pleick said

    There doesn’t seem to be anything unusual about using different marketing strategies for different target groups. At some level, all of us do this, and it comes rather naturally.

    Your point that telling the people that the homeopathic remedy will reduce symptoms, but won’t prevent the disease is important, because an emphasis on prevention could negatively affect the more mundance elements of the campaign (“the great social mobilization”) is interesting, and good thinking.
    Since such a campaign relies on the participation of the people (which are naturally forgetful and tend to do things as they have always done them), it makes you wonder if there are ways to make sure that participation levels are high. Specifically, if it could actually be helpful to add a magic pill to the package…
    I’m not implying that this was in any done intentionally. Rather, I’m wondering if strict evidence-based messages (“Do this. We’re not sure it will work specifically for you, but it helps in a statistical sense.”) aren’t somewhat self defeating. Don’t people expect positive, confident messages from their doctors? – 100% certainty. Which, for something like dengue fever prevention, is probably just as scientific as a magic pill. So, perhaps, the role of the magic pill is to trick some people into buying the rest of the package as well.

    • apgaylard said

      philippe: Thanks, as ever, for the thought-provoking comment. I Couldn’t agree more about the variation of strategy. It’s just that I found the use of different messages in different circumstances interesting. Regardless of intent, it could be quite a sensible survival strategy for a placebo therapy.

      I have been wondering whether the magic water rite could be thought of as validating a social contract; symbolising commitment. Perhaps if the ‘package’ of measures includes a group ‘medicine’ taking that passes on a more powerful message. Anyway, although it’s beyond me to make a meaningful sociological analysis, I think I can see that the placebo might be playing a complex role in this intervention.

      Does it justify the peddling of the placebo as medicine? I wouldn’t go that far. I think that the potential damages from spreading misinformation are too large. As I said in my first post, I think that testing the hypothesis that the homeopathic part of the strategy is superfluous would be a worthwhile (and ethical) experiment.

      Is it key to the intervention? Well, I think your point about percived risk/benefit at the level of the individual is well made. I have certainly heard people in England express the view that MMR only confers benefit at the level of the ‘herd’ so their child is not going to get the benefit – so why should they run the (actually relatively insignificant) risk? With infections that are transmitted person-to-person and have becomme relatively uncommon thanks, in some degree, to vaccination, I see that this argument poses a real risk to the intervention.

      However, I think that dengue in Brazil might be a bit different: you can see mosquitos and understand that they could infect you or a loved one directly. Also the incidence of dengue is high in these areas compared, say, to measles in my home town. So perhaps the combination of obvious, nasty, non-human vector and high incidence rates mean that the placebo element is not so important. Maybe the fines might help as well!

      Thanks for stopping by.

  2. pleick said

    APGaylard: thanks for your comments.

    I don’t know much about the dengue situation in Brazil, and perhaps my judgement is affected by some bias… But I’ve often observed that alternative medicine practicioners will bundle sensible advice (for example, on nutrition, exercise…) with more esoteric elements (such as homeopathic remedies). Naturally, this begs the question of whether the good advice wouldn’t work just as well without the magic. On the one hand, trust in evidence-based medicine and science is undermined. On the other hand, perhaps some people are reached that otherwise wouldn’t care about the good advice, and perhaps the efficiency of placebo and similar effects is higher…

    (There are plenty of exceptions, of course, where extremely stupid and dangerous advice is packed on top of the magic pills.)

    I think that in the long run, the damage that is done to scientific literacy far outweighs the potential benefits.
    We probably need some kind of cultural change: at the moment, there is a great distrust of science as a general enterprise. Think of discussions about LHC and black holes, nuclear power, genetic engineering, alternative medicine… Or how people boast about how they are no good at mathematics, which generally implies that mathematics is something that normal people shouldn’t have any business in.
    I certainly don’t want a return to a naively optimistic blind trust and admiration for science and technology; rather, a mature and critical appreciation of it.

    • apgaylard said

      philippe: “But I’ve often observed that alternative medicine practicioners will bundle sensible advice (for example, on nutrition, exercise…) with more esoteric elements”

      I’ve seen the same thing too. There has been some discussion at Science Based Medicine (can’t remember the exact post) of CAM appropriating this kind of sensible evidence-based advice and then using it’s success as evidence that CAM works.

      As for your comment on the cultural apsects: I couldn’t agree more.

      I appreciate your comments, as always.

  3. pleick said

    Well, I think your point about percived risk/benefit at the level of the individual is well made. I have certainly heard people in England express the view that MMR only confers benefit at the level of the ‘herd’ so their child is not going to get the benefit – so why should they run the (actually relatively insignificant) risk?

    The assessment of very small risks is something that people are notoriously poor at…

    I think the key point here, however, is not really the probability of serious vaccine side effects or serious consequences of measles… A disease is fate, something that happens. A vaccination, whether voluntary or compulsory, is something parents do to their child, in the sense that they’ll take the child to the doctor who administers the vaccine.
    The implication for the parents is that vaccine side effects are somehow their fault, while lasting damages due to a preventable disease aren’t.

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